While the role of major psychopathology has been addressed in the literature on sexual risk, relatively less attention has been placed on the personality disorders (PD). The chronic nature of the interpersonal dysfunction, impulsivity, and impaired decision making that characterize these disorders suggest that PD is an important predictor of sexual risk behavior engagement both prior to and after becoming infected with HIV. The present study builds upon the work generated by the Health Adherence Research Project (NIGMS S06 GM08101; Durvasula - PI), which suggests PD is a risk factor for riskier sexual practices. The proposed study will enroll a sample of 200 HIV+ and 200 HIV- sexually active adults (total N = 400), stratified by gender and sexual orientation and examine the relationship between psychopathology, particularly PD, and sexual risk behaviors. In addition, the intervening role of decision making on the PD-risk relationship will be examined. PD and major psychopathology will be assessed using multiple measures including structured psychiatric interviews. Sexual risk behaviors and drug and alcohol use will be assessed using a Time Line Follow-back (TLFB) Interview, a technique which will provide event level analysis of sexual behaviors, partners and contexts. Participants will be seen twice over 3 months, with psychiatric assessment administered at the baseline visit, and the TLFB administered at the 3 month follow-up. Given the hypothesized multi-determined nature of sexual behavior, multivariate techniques including Structural Equation Modeling using the EQS approach, MANOVA and regression will be used to test the simultaneous relationships between predictors, mediators and outcome. By describing this relationship using carefully elaborated indices of sexual risk in an urban, diverse sample, and identifying mechanisms by which PD and psychopathology influence sexual risk, particularly decision making, intervention programs can be developed which target the specific antecedents of risk experienced by this persons with PD. This grant will also further the development of the PI as an independent investigator and position her to pursue R34 and R01 level funding to continue this line of research.